I have to agree that degreasing a leader decreases the ability of the fish to identify the leader material.
There are three factors at work here and we tend to concentrate on only one of them - refractive index. The second is the residual oily sheen on the leader surface from the manufacturing process. The third is the fact that refractive index comes into play ONLY if the leader material is SUNKEN and completely surrounded by water. Degreasing eliminates factors two and three.
I cannot post references to other BB's but there is extensive evidence that removing the sheen and sinking the leader reduces the visibility of fluorocarbon. The sister BB of this site has numerous posts degreasers.
Both nylon and fluorocarbon are denser than water. Most nylon mono has a specific gravity between 1.1 and 1.2 compared to fluorocarbon at about 1.8. So fluorocarbon is 50% denser than nylon mono. One might think that this would cause the fluoro to sink but what it does is that it causes the fluorocarbon to indent
the meniscus more.
Since the depression of the meniscus increases the visibility of the floating line and it increases the refraction of light onto the river bottom, it makes the line more visible. It has been demonstrated that density of fuorocarbon in the sizes used for tippet will not sink by itself.
Fluorocarbon vs. Nylon | Fly Fish America
"....Surface tension—where the water’s surface behaves like an elastic film—must be broken before an object will sink. A object’s density and contact angle with the water’s surface are the two most significant variables in its ability to break surface tension and sink, and the “just slightly heavier than water” specific gravity and zero contact angle (i.e., laid out flat) of a nylon monofilament leader or tippet are not sufficient to do it most of the time. If pushed or pulled under the surface by a weighted fly or roiling current, nylon monofilament will sink . . . but very, very slowly.
Fluorocarbon has a specific gravity in the range of 1.75 to 1.90. Tungsten it ain’t, but it is significantly more dense than nylon. But is it sufficiently dense to quickly and reliable break surface tension and sink all by itself, even at zero contact angles, and even in the smallest diameters? No, it’s not. Our testing reveals that most brands of fluorocarbon tippet material in 0X to 8X diameters are no better than nylon at breaking surface tension and sinking on their own.
Larger diameter fluorocarbon materials do demonstrate a slightly better ability to break surface tension without the assistance of current or other external influences, but for practical fishing purposes fluorocarbon has little benefit over nylon on this measure."
A leader floating on surface tension, displaces the water surface just like a person lying on a trampoline displaces the surface. Since the water surface under the leader is now tilted and not horizontal, this creates mini windows that the fish can see just like the legs of an insect dimple the water surface allowing the trout to detect them even though they are theoretically outside of the "window". Since the light pattern is disrupted, it can be seen by the fish that are looking up AND by the fish that are looking down, because the disrupted light pattern is displayed on the stream bottom as well. This is important in still waters and the clear slow waters of spring creek type fishing situations where the water surface is smooth. It also only important IF the fish are wary enough that this change in light pattern (either by the floating leader or by leader sheen) puts the fish off.
That is why over in Europe where the fish are extremely heavily fished, they use leader degreasers
to remove the sheen and get the leaders to sink just below the surface. I think if you can make the leader less apparent to the fish, that is a good thing and I can't think of much of a downside to lowering visibility.
Commercial degreasers are commonly called "mud", such as Loon Snake River Mud
or "tippet degreaser" such as Airflow Tippet Degreaser
Degreasers do three things. First they contain a cleaner (detergent) that removes any oils or residual chemicals that are on the surface of commercial tippets. These oils prevent the leader from sinking. Secondly, they contain a sinkant or
(detergent) that destroys the surface tension of water molecules so the leader sinks immediately. Thirdly they contain fuller's earth compound that dulls the leader to remove the shiny surface so that the leader surface is less reflective. And finally, they contain a substance (glycerin) that keeps the degreaser from drying out.
If you look at the formula you may think that the only thing you have in your house is the detergent. However, you may already have a substitute for fuller's earth which is a special kind of bentonite clay. Bentonite is a clay material that anyone who visits Wyoming
for fishing has probably walked on. It is a common material in
and commercial bags of clay oil absorbent. So if you have clay cat litter or oil absorbent for your garage, you have the major ingredient for making your own degreaser.
Glycerin is used in commercial leader degreaser to keep it from drying out. If you don't have glycerin, you can get some at a drug store. It is used as an anti-constipation agent. However, it is not absolutely needed.
I make my own degreaser by crushing the clay to get the finest particles and then mix in Dawn or another dishwashing detergent to get a paste. I happen to have glycerin and so I also use it but you don't have to. I store the degreaser in a 35 mm film canister and rub it on the section of leader you want to sink.
Degreasers are different from sinkants such as Gerke's Xink
. These are liquids surfactants that you put on flies that you want to sink. They are commonly used on the marabou of wooly buggers so that they sink and absorb water from the very first cast. Another use is for small flies like midge pupa so they will sink faster. You can make your own sinkant as well.
, a wetting agent used in photo processing, is used by fly fishers to sink flies. The main ingredient in Photo Flow is ethylene glycol, which is also in antifreeze. Ethylene glycol disrupts the hydrogen bonding of water that creates the
surface film that supports flies. That is how ethylene glycol prevents water from freezing. So try some antifreeze as a wetting agent.